International Council for the Exploration of the Sea
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Report of the Joint NAMMCO/ICES Workshop on observation schemes for bycatch of mammals and birds (WKOSBOMB)

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posted on 2023-01-18, 11:08 authored by ICESICES

The Workshop was the result of an initiative from the North Atlantic Marine Mammal Commission who had expressed a wish to improve fishery by-catch monitoring among its Member States. Recognising that this is an area where the International Council for the Exploration of the Sea holds some expertise, a joint workshop was agreed with the aim of developing guidelines describing best practice for conducting marine mammal and seabird by-catch monitoring.
The workshop consisted of a series of informal invited presentations on a range of topics covering the agenda agreed by a joint NAMMCO/ICES steering group. Each presentation was followed by a group discussion focusing on the relevant topic. It was agreed that a manual providing guidelines for best practice would be drawn up after the workshop and would be published in the ICES Co-operative Research Re-port Series.  
By-catch monitoring is mandated under several national and international laws and agreements on both sides of the Atlantic and further afield. Schemes to monitor by-catch play an important role in the development towards and process of managing the oceans from an ecosystem perspective.
Usually by-catch monitoring is addressed through direct on board observer schemes, but these can be expensive to implement, particularly in the early exploratory phase when by-catch levels are not known and costly sampling effort may be focused in inappropriate areas. In such cases there are a number of other less direct approaches that can be used to obtain some initial information about possible by-catch levels.
Indirect approaches include the collation of anecdotal accounts, the systematic ex-amination of dead stranded animals or those found floating at sea, the examination of live animals by photo-monitoring for evidence of past entanglements, interviews of fishermen, collation of fishery logbook data, and through ‘parasitising’ or piggybacking on other research programmes.
Wherever possible, results from any of these methods should be compared with one another. An example was discussed from Iceland where porpoise by-catch rates from research surveys in a limited time and area were compared with results from a ques-tionnaire survey and with official logbook data. In this case by-catch rates calculated from logbook data were considerably lower than those estimated using the other methods by-catch.  
The workshop reviewed recruitment and training procedures using examples from the USA and the UK. Basic training and safety standards were outlined and the Workshop recommended that standardised training should be implemented at a European level for observers working on by-catch monitoring programmes in European fisheries.
Two further presentations examined the operational aspects of a marine mammal by-catch observer scheme in the USA and a seabird by-catch observer scheme in Chile. The Workshop was able to identify a number of useful and practical strategies and tactics for implementing such schemes.
Several alternative by-catch monitoring systems involving independent observations, but not relying on dedicated onboard observer programmes were discussed. A system of GPS-linked video surveillance was described on boats in Denmark, where by-catches of porpoises and seabirds had clearly been identified and recorded. 

In the USA a system employing an alternative platform has been developed, where two ob-servers used a fast power boat to monitor fishing operations by inshore gillnet vessels. Although daily costs were higher than using onboard observers, this approach enabled monitoring of a fleet sector that had been previously under-represented. An-other scheme was described in which Norwegian fishermen were paid to complete detailed activity and catch logs which had provided useful information on porpoise by-catch in coastal gillnet fisheries. Integrating fishery effort data with information on cetacean strandings and at-sea acoustic monitoring of porpoises in Polish waters was also described as another means of monitoring by-catch. Finally, the discard sam-pling scheme mandated at a European level under the data collection framework was also described, and its advantages and disadvantages as a means of collecting marine mammal and seabird by-catch data were discussed.
The Workshop discussed data collection methods and aspects of data and sample storage, and agreed that the retention of biological samples, including wherever possible whole animals, whilst logistically challenging, should be an important aim.
The Workshop discussed how fishing effort data can be used to plan and stratify sampling at sea, and how it can be used to raise observed by-catch rates to the fishery or fleet level. Problems with the reliability of effort data were described and dis-cussed. Some of the statistical methods for raising by-catch estimates were also re-viewed. It was stressed that there is not a single preferred way to determine overall total by-catch for a fishery, and that generally caution is required because sampling levels tend to be low and by-catches of protected species are generally rare events. It was also noted that total by-catch estimates are highly dependent on the raising factor, and that a detailed knowledge of the fishery is important to obtain the most reli-able estimates.
Finally the workshop considered relations between industry partners and by-catch monitoring programmes. It was stressed that transparency is critical to maintaining good relations with industry and examples from three EU funded projects were pre-sented to demonstrate this point.  
The workshop agreed that a summary report of the meeting would be produced but that a more detailed manual or set of guidelines on best practice would be drawn up and, with the prior agreement of ACOM, would be submitted to ICES for publication under its Cooperative Research Report Series. 


Published under the auspices of the following ICES Steering Group or Committee

  • ACOM

Published under the auspices of the following ICES Expert Group or Strategic Initiative

WKOSBOMB; Workshops - ACOM


ICES Expert Group Reports

Meeting details

28 June-1 July 2010; Copenhagen, Denmark

Recommended citation

ICES. 2011. Report of the Joint NAMMCO/ICES Workshop on observation schemes for bycatch of mammals and birds (WKOSBOMB) , 28 June-1 July 2010, ICES, Denmark. ICES CM 2010/ACOM: 33. 40 pp.